Mechanical stoker for boiler and like furnaces.



G. DE GRAHL.

MECHANICAL STOKER FOR BOILER AND LIKE FURNACES.

APPLICATION FILED 00 129, 1912. v

w m u T V m a 4 m w 7 a f 6 5 8 W 9 0 W L 1 r G. DB GRAHL.

MECHANICAL STOKER FOR. BOILER AND LIKE FURNACES.

APPLICATION FILED OGT. 29, 1912.

1,09 ,5 5, Patented June 2, 1914.

5 SHEETSSHEET 2.

G. DE GRAHL.

MECHANICAL STOKER FOR BOILER AND LIKE FURNACES.

APPLICATION FILED OCT. 29, 1912.

Patented June 2, 1914.

5 SHEETS-SHEET 3.

I WWVA/ C. DE GRAHL.

MECHANICAL STOKER FOR BOILER AND LIKE FURNACES.

APPLICATION FILED OCT. 29, 1912.

Patented June .2, 1914.

6 SHEETS-SHEET 4.

zzw

G. DE GRAHL.

MECHANICAL STOKER FOB. BOILER AND LIKE runmcss. v APPLIOATION FILED OUT. 29, 1912. 7 1 098 565. I Patented June .2, 1914.

6 SHEETS-SHEET 5.

I QFFICE.

GUSTAV m: GRAHL, OF ZEHLENDOR-F, GERMANY.

MEGHANIGAL STOKER FOB, BOILER AND LIKE FURNACES.

To all whom it may concern Be it known that I, GUSTAV DE GRAHL, a subject of the Emperor of Germany, resid ing at Zehlendorf, near Berlin, Germany, have. invented certain new and useful Improvements in Mechanical Stokers for Boiler and like Furnaces, of which the following is a specification.

This invention relates to mechanical stoleers of the type in which the fuel is fed into the furnace from below.

In a stoker according to the present invention, one or more scoops are adapted to revolve about a horizontal axis or shaft adjacent to a fuel chute and to the grate of the furnace, so that the scoop or scoops raise the fuel from the chute into the furnace, the fuel being discharged from each scoop when it reaches the furnace by means of a rake operated during one part of the revolution of the scoop.

The invention difl'ers from mechanical stokers hitherto in use in that the usual prisinatic coal box or hopper, arranged in front of the furnace and from the bottom of which hopper the fuel is injected into the furnace by a die or ram, is dispensed with, which is a great advantage, particularly in the ap plication to locomotive furnaces as well as in the application to internal furnaces, as by the simultaneous rotary movement of the scoops and the operation of the rakes, the fuel is not only lifted up to the grate but, if required, may also be fed forward.

The accompanying drawings illustrate by way of example one form of the invention applied to locomotive boiler furnace.

Figure 1 a side sectional elevation, the section being taken through the fire box and mechanical stokcr. Fig. 2 is an end sectional elevation corresponding to Fig. 1.

Fig. 3 is a side elevation illustrating the mechanism for intermittently'rotating the drum in which the scoops are formed, the drum itself being omitted. Fig. 4- is a detail view of the slotted oscillatory lover, Fig. 5 being a section on the line AB Fig. i. Fig. 6 is a side sectional elevation on a larger scale showing the drum with the scoops and the adjacent parts of the fire her; and fuel chute. Figs. 7 and 8 are, respectively, a plan and a side view of the drum and the cams for operating the rakes, part of the casing to which the cams are se- Speeification of Letters Patent.

Application filed October 29, 1912.

Patented June 2, 1914'. Serial No. 728,395.

cured being shown in Fig. 7 but omitted in Fig. 8. Figs. 9 and 10 are end views illustrating a modification in which the drum is provided with two scoops fitted with rakes which are interconnected and only one cam is needed for operating them, the figures showing the rakes in two different positions.

In carrying out the invention according to one form and as illustrated in Figs. 1 to 6, the fire box 1, of the locomotive is provided at the bottom with a grate2, which may be built up of fire bars in any usual manner, and below which grate is arranged the ashpit 3. A fuel chute 1, conducts the fuel from any suitable form of storage receptacle, the coal or other fuel sliding down the chute into .a position opposite to the Stoker.

The stoking apparatus proper comprises a drum 5, revolubly mounted on ashaft 6, which may conveniently be one of the axles of the locomotive. The upper part of the periphery of this drum is adjacent to the front end of the grate. A ratchet wheel 7 is rigidly connected to the drum 5, and is adapted to be intermittently rotated by means of a awl 9, mounted upon a rocking lever 8, free y mounted on the shaft 6. The rocking lever 8, is connected by a rod 10, to a slider 11, adapted to slide in a slotted oscillatory lever 13, mounted on trunnions 12. The slider 11, is adapted to be held in any desired position in the slotted oscillatory lever 13, and accordingly as it is maintained at a greater or less distance from the pivotal axis 12, of the oscillatory lever 13, so will the degree of oscillation of the rocking lever 8, be increased or lessened, there being no movement when the slider 11, coincides with the axis 12. For the purpose of adjusting the slider, the rod 10, is connected by a link 14, to a bell-crank lever 16, pivoted at 15, and connected by a rod 17, to a hand lever 19, pivoted at 18, provided with a handle 20, and with any usual form of locking device, such as a lever 23, secured to the handle at 22, and provided with a link 24, carrying a tooth 25, adapted to be engaged in any of the teeth of a quadrant 21. Thus, according to the position of the hand lever 19, in relation to the quadrant 21, so will the position of the slider 11, in relation to the fulcrum or pivotal axis 12,

take the form of blades or shovels.

of the slotted lever 13, be varied and, con sequently, so will the degree of oscillation of the pawl lever 8, be varied with a consequent variation in the degree of rotation of the drum. The oscillatory lever 13, may be oscillated by. any convenient mechanism, for instance, by means of an eccentric 30, mounted on one of the axles 29, the strap 28, of the eccentric being connected by a rod 27, to the lever 1.8, by a. pivotal joint 26. Thus, when the axle 29, is rotated the eccentric 30, will cause the oscillatorylever 13, to oscillate and ifthe slider 11, heremote from the axis 12, the rocking lever 8, will also oscillate and through the medium of its pawl 9, and the ratchet wheel 7, will impart an intermittent rotary motion to the drum 5, in the direction of the arrow 31, Figs. 1 and 6. Obviously, instead of the rod 27, being connected to the oscillatory lever 13, and the rod 10 to the slider 11, the rod 10, may be connected to the oscillatory lever 13, and the slider 11, to'the rod 27, an identical action resulting.

The cylindrical surface of the drum 5, is provided, for example, with three longitudinal poclrets 32, forming the mouths of scoops 36, as indicated in Figs. 1, 2, 6 and 7. Rakes 34, are pivotally mounted within the scoops, for instance, by means of pins 38, entering holes or bearings in the end walls of the drum. The rakes are preferably in the form of grids, although they may be of any other suitable form, as for instance, they may They are intended to occupy either of two positions alternately, namely, inwardly against the abutments 35., in which case the scoops are open, ready to receive fuel, or flush with the cylindrical surface of the drum as indicated at 34, in which case the scoops are closed. Mechanism hereinafter described is provided for movin the rakes, so that while each scoop approac es the fuel chute 4, and is passing the same, and until it approaches the grate, the rake is retained in its inward position against the abutment 35, sothat the scoop is charged with fuel which it carries upto the grate. As it approaches the grate the rake begins to move outwardly and discharges the fuel from the scoop into the furnace, the combined rotary movement of the scoop and oscillatory movement of the rake,

also tending to feed forward the fuel on the grate. The rake is maintained in its outward position until it has passed beyond the front end of the grate, so that it acts as a temporary extension thereto until the following part of the plain cylindrical surface of the drum meets the grate and so avoids any liability for the fuel in the furnace to return to the scoop. After this the rake is moved inwardly, so that the scoop is ready to approach the fuel chute and receive another charge.

, noeaaee pin 33, and, consequently, of its rake 34;. As

will be seen from Fig. 8, while each of the pins 33, moves through the lower are of its travel around the axle 6, it will be held by the cam ll, acting on the respective roller 39, in such a position that its corresponding rake 34, is in its retracted position, that is to say, bearing against the abutment 35,. thus permitting fuel to enter the scoop through its pocket 32, as it passes the fuel chute 4. As each pin 33, moves through the upper arc of its travel its corresponding roller 39, engages with the cam 40, so that the roller mounts the cam 4:0, and the pin 33, is rotated, the ralre 34:, being moved into the outermost position 34. The fuel raised on the rake is thus discharged into the furnace until the rake completely closes the pocket 32, of its scoop. Owing to the fact that the rake executes its oscillatory move ment simultaneously with the revolution of the drum the fuel is not only raised into the furnace, but is also moved forward toward the tube plate of the boiler. Each rake 34-, does not leave the position in which it closes the pocket 32, until its roller 39, has moved out of range of the cam 40, which insures that the rake does not reccde into the drum until it has left the grate, so that the fuel cannot return from the furnace into the scoop as mentioned above. When each roller 39, moves into the range of the cam 41, the rake is positively moved from the position 84, back against the abutment 35, and is held in this position while the fuel is again being admitted to the scoop, and so long as the roller 39, runs along the cam 41.

As will be understood from the above the fuel executes athree-fold movement, that is to say, firstly, it is moved by the rotary movement of the scoop, up to the front end of the grate, secondly, it is lifted by the operation of the rake over the grate into the furnace, and, thirdly, it is advanced in the furnace owing to the combined or simultaneous rota movements of the rake and scoop. Of t ese three movements of the fuel one or the other may be dispensed with without departing from the spirit of this invention. v

The farther the slider 11, is moved from the fulcrum 12, of the oscillatory lever 13, by the operation of the hand lever 19, the greater will be the rocking movement of the lever 8, and pawl 9, and, consequently, also the greater will be each feeding movement of the drum. Thus, by suitably adjusting the slider in relation to the link, the feeding movement of the drum and, consequently, the supply of fuel to the furnace, may be correspondingly regulated.

If it is desired to interrupt the fuel supply it is only necessary to adjust the slider 11, so as to make its axis of rotation coincident with the axis of oscillation of the lever 13.

The cams a0 and 41, hereinbefore referred to may take any desired form, such as abutments, rollers, inclined planes, or the like and similarly any required number of scoops may be employed. In some cases even one single scoop revolving about the aXle 6, may be sufficient. Further, the cam 41, may be dispensed with if a positive movement of the rakes 34, is produced, for ex ample by interconnecting .the pins 38, by connecting rods or other suitable means. Such a modification is illustrated in Figs. 9 and 10which show a drum provided with two scoops fitted with rakes so interconnected. In order to effect a proper movement of the two rakes 34, only one cam 40, is provided, which moves or rocks one rake 34, at a time. The cam brings the rake up to the cylindrical surface of the drum where it is held to close the pocket or mouth of the scoop until it approaches the lower section of its circular track or path of movement. The two rakes 34, are interconnected by a connecting rod 45, which is pivotally attached to the two levers 37, at 46, 46. By means of this arrangement as soon as one rake is moved by the cam 40, outward to- 'ward the cylindrical surface of the drum,

the other rake moves in toward the interior of the drum ready to allow fuel to enter the corresponding scoop. The arrangement just described may of course be adopted in connection with drums provided with more than two scoops.

I claim:

1. A mechanical stokervfor boiler or like furnaces comprising a stationary furnace grate for receiving the fuel, a fuel chute and means for raising the fuel' from said chute to the front of said furnace grate, consisting of a shaft and a drum revolubly mounted on said shaft and provided with a fuel pocket having a movable bottom, and means for moving said bottom outwardly from the interior to the periphery of said drum in discharging the fuel upon the grate and for moving sald bottom from the periphery to the interior of the drum when receiving fuel from the fuel chute, the upper part of the periphery of said drum being adjacent to the front of said grate and means for revoli ing said drum.

2. A mechanical stoker for boiler or like furnaces comprising a stationary furnace greate for the reception of the fuel, a fuel chute, means for raising the fuel from said chute to the front of the furnace grate consisting of a shaft and a drum revolubly mounted on said shaft and provided with a fuel pocket having a movable bottom being formed by a' rake, pivotally mounted in said drum, means for moving said bottomcutwardly from the interior to the periphery of the drum in discharging the fuel upon the grate and for moving said bottom fromthc periphery to the interior of the drum, when receiving fuel from the fuel chute, the upper part of the periphery of said drum being adjacent to the front of said grate, and means for revolving said drum.

3. A mechanical stoker for boiler or like furnaces comprising a stationary furnace grate for the purpose of receiving fuel, a fuel chute, and means for raising the fuel from said chute to the front of the furnace grate consisting of a shaft and a drum revolubly mounted on said shaft and provided with a. fuel pocket having a movable bot tom, means for moving said bottom outwardly from the interior to the periphery of the drum in discharging the fuel upon the grate and for moving said bottom from the periphery to the interior of the drum, when receiving fuel from the fuel chute, comprising a lever operatively connected with said bottom and carrying a roller and s'iriiionary means adjacent to the aforesaid ti. on for engaging with said roller, the upper part of the periphery of said drum being adjacent to the front of said grate, and means for revolving said drum.

4. A mechanical stoker for boiler or like furnaces comprising a stationary furnace grate for receiving the fuel, a fuel chute and means for raising the fuel from said chute to the front of the furnace grate, consisting of a shaft and a drum revolubly mounted on said shaft and provided with a plurality of fuel pockets having movable bottoms, means for moving said bottoms outwardly from the interior to the periphery of the drum in discharging the fuel upon the grate and for moving said bottoms from the periphery to the interior of the drums, when receiving fuel from the fuel chute, the upper part of the periphery of said drum being adjacent to the front of said grate, and means for revolving said drum.

5. A mechanical stoker for boiler or like furnaces comprising a stationary furnace grate for receiving the fuel, a fuel chute,

and means for raising the fuel from said from the periphery to the interior of the i upper park; of the periphery e"? ti'u uriun, when receiving fue from the fuel I 121mm being m ijaeent the tfrlmt 1" chute, comprising two levers interconnectefii grate, zmci means for revolving said (I by a connecting rod and. epemtively con QF UEETEHJ' 11w:- ERA]. 3 nested W151 said bettoms each carrying; a Wiitneseee:

teller, stationery means adjacent to the said W'ommmm drum for engaging- With said I'QHLWQ the 

